(a) Field of the Invention
The present invention relates to a metal foam, and more particularly, to an open-porous metal foam.
(b) Description of the Related Art
A metal foam may be used in various fields due to a low weight and porosity. Particularly, the metal foam may be catalytically activated for the purpose of a chemical process or may be used in an environmental engineering, and may be used for the purpose of filtration.
In addition, the metal foam is frequently used at a relatively high temperature and a severe environment. In this case, the metal foam should endure the high temperature of 700° C. or more, and particularly, even the temperature at which it is difficult to make most metals and metal alloys stable for a long time such as the high temperature of 1000° C. or more.
The metal foam is advantageous in that the metal foam is applied for the purpose of high temperature as compared to a general heat resistant metal or heat resistant metal alloy in terms of manufacturing costs.
Meanwhile, the metal foam may be manufactured by various methods. In the related art, a cost may be more reduced by sintering a green body manufactured in a powder form by using each metal.
However, all characteristics required in the completed metal foam cannot be satisfied by only a sintering process.
Accordingly, it is known that the surface of the metal foam is subsequently coated and reformed. This is required in a metal foam that is generally formed of nickel.
In the related art, an open-porous shaped body that is coated by another metal formed of nickel or iron, and a mixed crystal of at least iron or nickel, or an intermetallic phase is disclosed.
The completed open-porous shaped body is formed of at least two phases having different thermal, mechanical and chemical characteristics.
In addition, in the related art, the use of the metal foam formed of an iron-chrome-aluminum alloy is disclosed, and a metal oxide layer acting as a catalyst is formed on the metal foam. However, the used alloy is not disclosed in detail, and a ratio at which each metal is included in the alloy and a manufacturing process of the metal foam are not disclosed.
In addition, particularly, it is impossible or very difficult to sinter the alloys including aluminum in a relatively higher ratio.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.